{"product_id":"allen-bradley-1756-dh485-communication-interface-module","title":"Allen-Bradley 1756-DH485 Communication Interface Module","description":"\u003ch1\u003eAllen-Bradley 1756-DH485 Communication Interface Module\u003c\/h1\u003e\n\u003cp\u003eThe\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen-Bradley 1756-DH485\u003c\/strong\u003e, also cataloged as the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e1756-DH485 communication interface module\u003c\/strong\u003e, serves as the primary\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eDH-485 network gateway interface unit\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eutilized to execute protocol bridging between\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eControlLogix Logix5000 controllers and legacy DH-485 device networks\u003c\/strong\u003e. It provides deterministic backplane-to-fieldbus conversion for serial network integration within 1756 chassis architectures.\u003c\/p\u003e\n\u003ch3\u003eSuffix Breakdown \u0026amp; Model Matrix\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eBase model: 1756-DH485 communication module\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eNo functional suffix segmentation defined\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eConfiguration is fixed to DH-485 protocol implementation within ControlLogix platform\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003ctable class=\"w-fit min-w-(--thread-content-width)\"\u003e\n\u003cthead\u003e\n\u003ctr class=\"firstRow\"\u003e\n\u003cth class=\"last:pe-10\"\u003eParameter\u003c\/th\u003e\n\u003cth class=\"last:pe-10\"\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003e1756-DH485\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eAllen-Bradley\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eUSA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.5 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e145 mm × 35 mm × 140 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e0 deg C to +60 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003eSupplied via ControlLogix backplane\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNetwork Type\u003c\/td\u003e\n\u003ctd\u003eDH-485 (Data Highway 485)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBaud Rates\u003c\/td\u003e\n\u003ctd\u003e9600, 19.2k, 57.6k bps\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMax Nodes\u003c\/td\u003e\n\u003ctd\u003eUp to 32 devices\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConnector Type\u003c\/td\u003e\n\u003ctd\u003e6-pin Phoenix connector\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCable Type\u003c\/td\u003e\n\u003ctd\u003eShielded twisted-pair RS-485\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStorage Temperature\u003c\/td\u003e\n\u003ctd\u003e–40 deg C to +85 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHumidity\u003c\/td\u003e\n\u003ctd\u003e5%–95% non-condensing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCertification\u003c\/td\u003e\n\u003ctd\u003eUL, CE, CSA, ATEX, IECEx\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eBackplane Bus Communication and DH-485 Protocol Bridging Behavior\u003c\/h3\u003e\n\u003cp\u003eThe module executes protocol translation between ControlLogix backplane messaging structures and DH-485 serial frame formats. Data encapsulation is handled through internal buffering aligned to Logix5000 task scheduling cycles.\u003c\/p\u003e\n\u003cp\u003eEtherNet\/IP is not natively involved in DH-485 transport; instead, RS-485 physical layer signaling governs field communication timing. Deterministic access is maintained via token-passing behavior inherent to DH-485 topology, limiting collision conditions across up to 32 nodes.\u003c\/p\u003e\n\u003cp\u003eBackplane communication is synchronized with chassis scan cycles, ensuring consistent update mapping between controller tags and legacy device registers without external protocol conversion hardware.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQ)\u003c\/h3\u003e\n\u003cp\u003eQ: Does the 1756-DH485 support Ethernet\/IP communication directly?\u003cbr\u003eA: No. The module only provides DH-485 protocol connectivity and relies on backplane integration for Logix controllers.\u003c\/p\u003e\n\u003cp\u003eQ: Can the module operate on multiple DH-485 channels simultaneously?\u003cbr\u003eA: Yes. It supports two DH-485 communication channels within a single module architecture.\u003c\/p\u003e\n\u003cp\u003eQ: Is hot-swap supported during active network communication?\u003cbr\u003eA: Yes. The module supports hot-swapping within a ControlLogix chassis, but communication sessions will reset during replacement.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eInstall the module into a certified 1756 ControlLogix chassis slot with confirmed backplane alignment. Ensure full connector seating to maintain stable DH-485 routing via internal interface circuits.\u003c\/p\u003e\n\u003cp\u003eUse shielded twisted-pair RS-485 cable for DH-485 network connections. Maintain continuous shield termination and single-point grounding to reduce noise coupling across legacy serial segments.\u003c\/p\u003e\n\u003cp\u003eRoute DH-485 cabling separately from high-voltage switching and motor drive lines. Verify node addressing and baud rate consistency across all devices before initiating network communication.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43578826719322,"sku":"1756-DH485","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1756-CN2RK1.jpg?v=1782876376","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1756-dh485-communication-interface-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}